Homing in on asthma

Target genes that may predispose individuals to developing asthma or allergic diseases are a step closer to being identified, reports a study this week in Nature Immunology.

According to previous genome-wide association studies (GWAS), there are currently more than 1500 potential targets associated with asthmatic disease, which is too large a number to allow researchers to determine their individual relevance to the disease process. T cells-a subset of white blood cells and a key part of the immune response-have long been associated with asthma.

Pandurangan Vijayanand and colleagues collected small amounts of blood from healthy subjects and asthmatic patients, and looked at epigenetic markers in their T cells. Specifically, they looked for a modification, known as H3K4me2, which is associated with genomic enhancers that increase the likelihood of expressing certain genes. They found differences in the H3K4me2 profile in T cells from asthmatic versus healthy individuals.

They then used their research, in addition to other published human genomic datasets and GWAS, to narrow down the 1500 potentials to about 38 target locations. This is a much more manageable number of implicated genes to test for their relevance in asthma.